---
id: CVE-2026-73459
title: >-
  On affected platforms running Arista EOS with IS-IS configured, an
  unauthenticated attacker who can inject a specially crafted IS-IS LSP PDU can
  cause the legitimate LSP to be unexpectedly purged from the IS-IS link-state
  database
summary: >-
  On affected platforms running Arista EOS with IS-IS configured, an
  unauthenticated attacker who can inject a specially crafted IS-IS LSP PDU can
  cause the legitimate LSP to be unexpectedly purged from the IS-IS link-state
  database. This …
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'
cwe:
  - CWE-354
vendor: Arista Networks
product: EOS
affected:
  - EOS >= 4.36.0 <= 4.36.1F
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T20:17:27.570'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73459'
references:
  - url: >-
      https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160
    label: psirt@arista.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-16T19:34:28.975379Z'
ingestedAt: '2026-09-15T23:46:25.573Z'
epss: 0.00164
epssPercentile: 0.05996
---

## Overview

On affected platforms running Arista EOS with IS-IS configured, an unauthenticated attacker who can inject a specially crafted IS-IS LSP PDU can cause the legitimate LSP to be unexpectedly purged from the IS-IS link-state database. This may result in traffic loss.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.